1. Field of Invention
This application generally relates to a blank cartridge and chamber for use in simulated firearms not capable of discharging projectiles.
2. Prior Art
Blank cartridges are used to simulate the visual and auditory effects of ammunition cartridges. Blank cartridges include a primed case and propellant but do not have projectiles as do ammunition cartridges. The lack of a projectile permits blank cartridges to be used safely for training, theatrical, educational, and recreational purposes.
Simulated firearms are intended as safer substitutes of actual firearms for training, educational, recreational, and theatrical purposes. Simulated firearms are intended to appear like actual firearms and produce the realistic sound and visual effects of gunfire. Simulated firearms may have magazines as do actual firearms. The essential difference of simulated firearms from actual firearms is that simulated firearms cannot discharge projectiles. This characteristic makes simulated firearms safer for many uses and can exempt the devices from significant legal restrictions controlling the sale, use, and possession of actual firearms.
Blank cartridges operate similarly to firearm cartridges in general. A blank cartridge is slidably inserted into a chamber of corresponding internal dimensions. A firearm bolt is closed, seating the cartridge upon the cartridge neck, case mouth, cartridge shoulder, or case rim. A striker is forwardly released through the bolt face to impact and detonate the primer. The resulting flash is ported through one or more flash paths to the interior of the cartridge. The propellant ignites and generates highly pressurized exhaust gases. The exhaust gases are vented from the cartridge and exit through the chamber.
A cartridge, whether blank or ammunition, may be used only in a chamber of mated physical dimensions. If the cartridge does not mate within the chamber, it will not seat and be incapable of discharging. Even minor dimensional variations can prevent a cartridge from operably seating within a chamber and may cause dangerously elevated gas pressures. These dimensional constraints restrict the cartridges that may be employed in a chamber and prevent the use of unsafe cartridges.
There are two main types of blank cartridges. The first type has exterior dimensions similar to ammunition cartridges and is intended for use in actual projectile-discharging firearms. This type of blank cartridge is thus interoperable with ammunition cartridges. An example is the 5.56×45 mm blank cartridge. This blank cartridge is interoperable with the 5.56 mm×45 mm military ammunition cartridge. The 5.56×45 mm blank cartridge vents exhaust gases in a forward direction like the related ammunition cartridge, generating realistic visual and auditory effects. This blank cartridge can cycle the action of an automatic firearm chambered for the ammunition cartridge. The disadvantage with this type of blank cartridge is that its interoperability with ammunition cartridges always risks the accidental loading and discharge of an ammunition cartridge. The inadvertent discharge of a projectile cartridge is known to cause serious damage, injury, or death.
The second type of blank cartridge is inoperable in the chamber of projectile-discharging firearms. These blank cartridges have external dimensions different from ammunition cartridges and are only operable with the mated chambers of simulated firearms. An example is the rimless 8 mm Fiocchi blank cartridge and chamber for simulated firearms. The Fiocchi blank cartridge has a flat nose which is different from the rounded bullet of a bottleneck ammunition cartridge. The Fiocchi blank cartridge and blank chamber also operate differently from ammunition cartridges and chambers. The Fiocchi cartridge is seated and detonated within the Fiocchi chamber. Instead of directing the exhaust gases in a forward direction, the Fiocchi blank cartridge ports exhaust gases laterally in a direction perpendicular to the axis of the blank cartridge. The exhaust gases are vented from the blank chamber in a similar direction lateral to the axis of the chamber. The exhaust gases are not vented through the barrel. This type of gas venting prevents a projectile from being discharged through the muzzle of the simulated firearm. However this gas venting does not create realistic visual and auditory effects. The flat nose also limits the internal capacity for propellant and restricts the volume of propellant available for visual and auditory effects. This limited propellant capacity also reduces the energy for cycling the actions of larger automatic simulated firearms. The external profile of the flat nose can cause feeding problems when employed in the magazines of automatic simulated firearms. Finally, blank cartridges adapted for this unconventional lateral porting of exhaust gases are more expensive to manufacture than other blank cartridges.